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Partnering with WREN, questionnaires are sent to offshore wind energy developers around the world who are involved in environmental monitoring. This page provides contextual project information and highlights environmental monitoring, providing links to available data and reports. Content is updated annually.

Unitech Zefyros (Hywind Demo)

wind farm

Contents

Wind Project Site

Title: Unitech Zefyros (Hywind Demo)
Status:
Operating
Project Manager:
Norwegian Offshore Wind
Turbine Developer:
Siemens
Foundation Manufacturer:
Technip Energies
Construction Start:
Operation Start:
Info Last Updated:
Contact:
Alex Williams
(login for email address)
Website:
External Link

Details

Technology:
Floating Offshore Wind
Project Scale:
Demonstration
Turbine Model:
SWT-2.3-82
Hub Height:
65 m
Rotor Diameter:
82.4 m
Number of Turbines:
1
Capacity per Turbine:
2.3 MW
Installed Capacity:
2.3 MW
Support Structure:
SPAR Buoy
Inter-Array Cables:
22 kV
Export Cables:
Unburied Seafloor Cables
Export Cable Voltage:
22 kV
Number of Export Cables:
1
Cable Landfall:
Trenched
Physical Site:
Deep Water (>60m), Marine, Hard-Bottom Habitat
Water Depth:
60-200 m
Distance from Shore:
10-13 km
Country:
Norway

Description

The Unitech Zefyros began its journey as Hywind Demo, the world’s first floating offshore wind turbine, installed by Equinor (formerly Statoil) in 2009 at the METCentre test site. This 2.3 MW turbine successfully demonstrated its ability to perform in all wind and wave conditions during eight years of operation off the Karmøy test location. The Hywind Demo project proved the viability of the floating wind turbine concept and ultimately led to the development of the world’s first commercial floating wind farm, Hywind Scotland.

In 2019, ownership of the turbine was transferred to Unitech Offshore, which renamed it Unitech Zefyros. Now operating under its own concession, Zefyros plays a key role in research and technology development as part of the Sustainable Energy Katapult and serves as infrastructure at the METCentre test site. Additionally, it supports power delivery to the local grid onshore, with TetraSpar feeding energy through Zefyros.

Location

The Unitech Zefyros is located in Norway, approximately 10 km (6.2 miles) offshore from Karmøy, as part of the METCentre test site for offshore wind turbines. This site is a critical hub for testing and developing new floating wind turbine technologies and is situated near deepwater quays and shipyards. The nearest ports are on the coast of Karmøy and in the nearby town of Haugesund.

Project Timeline

  • November 2022: Zepfyros mounted a helicopter deck
  • October 2021: Performance monitoring
  • 2020: Consideration for electrolysis to produce hydrogen
  • 2019: Unitech Offshore took ownership from Equinor and renamed Unitech Zeyphros
  • May 2014: Performance monitoring
  • December 2009: Turbine fully commissioned
  • September 2009: Turbine connected to grid and generated power
  • June 2009: Turbine installed
  • November 2005: Consent application submitted

Licensing Information

In January 2005, the Norwegian Government granted consent authorization for the Hywind Demo project (now known as Unitech Zefyros). On 20 September 2022, METCentre was granted a license, by Norwegian authorities, to expand its testing capacity for floating energy production near Karmøy. The approval, valid for 25 years, allowed for the installation of up to seven turbines with the necessary cabling for power generation. The consenting process involved coordination with multiple regulatory agencies, including the Norwegian Water Resources and Energy Directorate (NVE), the Norwegian Directorate of Fisheries, and the Norwegian Environment Agency. 

Key Environmental Issues

There are limited publicly available studies detailing ecological monitoring at Hywind Demo / Unitech Zefyros, however, an acoustic monitoring study was conducted, and an ocean buoy was deployed to collect data. Monitoring efforts mainly focused on the turbine’s operational performance and structural behavior.

Environmental Monitoring: Unitech Zefyros (Hywind Demo)

ID Phase Stressor & Receptor Design and Methods Results Publications Data
2131846 Construction, Operations Changes in Flow

Physical Environment 		Buoy-Based Site Assessment
A Seawatch buoy monitored metocean parameters (wind speed, wave heights, ocean currents) from August 2009 to September 2011. Measure-Correlate-Predict algorithm extrapolated long-term wind conditions using Utsira meteorological station data. Extreme conditions were estimated with Gumbel distributions fitted to annualized peaks, while Weibull distributions described currents and wave heights. 		Complete
Seasonal variations showed maximum metocean parameters in late winter, with flow directions parallel to the coastline. Measurements revealed mean wind gusts of 9.0 m/s and significant wave heights of 1.5 m, with maximums of 26.7 m/s (wind) and 15.8 m (wave). Extrapolated 50-year extremes included 30.5 m/s wind gusts, 13.3 m wave heights, and 1.4 m/s currents at 20m depth. 		Onstad et al. 2016

No data available
2131845 Operations Noise

Marine Mammals 		Underwater Acoustic Recording Assessment
In August 2011, JASCO deployed an array of AMAR acoustic recorders at two sites—one at the Hywind Demo and one at a control site 10 km away—capturing 100% data during a 150-day recording program. 		Complete
The Hywind station recorded significantly more high-level acoustic events than the control station. Sound levels at both locations decreased linearly from 50 Hz to 20 kHz, but the Hywind station uniquely displayed a peak at 25 Hz with harmonics at 50 Hz (weak), 100 Hz (weak), and 150 Hz (pronounced). These tonal patterns likely originated from electrical equipment in the mooring system. 		Martin et al. 2011

No data available